B. L. Siracuse1,4, K. Mahendraraj1, R. S. Chamberlain1,2,3 1Saint Barnabas Medical Center,Department Of Surgery,Livingston, NJ, USA 2New Jersey Medical School,Department Of Surgery,Newark, NJ, USA 3St. George’s University School Of Medicine,St. George’s, St. George’s, Grenada 4Duke University,Durham, NC, USA
Introduction: Small cell gastric carcinoma (SCGC) is an aggressive neuroendocrine malignancy that comprises less than 0.1% of all gastric carcinomas. No large patient series exist and clinical information regarding SCGC is derived from limited case studies. This study sought to examine the demographic and clinical factors in a large cohort of SCGC patients in order to compare clinical outcomes of SCGC to the more common gastric adenocarcinoma (GA).
Methods: Demographic and clinical data on 71,607 patients with gastric cancer was abstracted from the SEER database (1973-2010). 207 SCGC and 71,400 GA patients formed the study populations. Abstracted data was analyzed using Chi square tests, t-tests, and multivariate analysis. Kaplan-Meier analysis was used to compare long-term survival between the groups.
Results: SCGC comprised 0.3% of all gastric cancers identified. The mean age of SCGC and GA patients was similar (68±12 vs.70±13 years, p=0.03) and both cancers were more common in males (64.7% and 66.0%, p<0.001) and Caucasians (70.4% and 65.6%, p<0.001). SCGC was more often undifferentiated (66.9%vs.2.9%, p<0.001) and had more lymph node positivity (59.6% vs. 55.9%, p=0.01) and metastatic disease than GA (64.5% vs. 46.1%, p<0.001). SCGC had lower mean survival times than GA (1.00±1.78 vs. 2.02±3.91 years, p=0.03). Mean survival time for SCGC patients treated with radiation was inferior to GA, but SCGC patients benefited more from surgery than GA patients (2.20±0.61 vs. 1.23±0.04 years, p<0.001). Multivariate analysis identified tumor size greater than 2 cm (OR=2.1, CI=1.9-2.4), regional (OR=2.8, CI=2.6-3.0) or distant disease (OR=2.1, CI=1.9-2.4), lymph node positivity (OR=1.6, CI=1.4-1.8), undifferentiated grade (OR=1.3, CI=1.1-1.4), Caucasian race (OR=2.0, CI=1.8-2.2), and male gender (OR=1.2, CI=1.1-1.3) as independently associated with increased mortality for SCGC, p<0.001. A survival advantage for SCGC was seen in patients treated with surgery alone (OR=0.5, CI=0.4-0.6) or in combination with radiation (OR=0.23, CI=0.2-0.3), p<0.001.
Conclusion: SCGC is a rare and often lethal gastric malignancy that presents most often in Caucasian males in their seventh decade of life, with larger tumor size, more undifferentiated histology, greater lymph node positivity, and higher rates of metastatic disease than GA. The majority of SCGC was untreated presumably due to advanced disease, but when treatment was employed, surgical resection resulted in a greater survival advantage than similarly treated GA. The combination of surgery and radiation was associated with the longest survival compared to other treatment modalities for SCGC, and should therefore be considered in patients with operable disease.
